Some, like the one in the pic, have two wheels in front, one in back.
Others, like the ONLY trike I've ever ridden, have one 'way out front and two in the rear.
That machine belonged to one of my former students. He drove up for a lesson with it and I was immediately knocked out...
It was a BIG V-8 with an automatic tranny... had obviously been a front-wheel drive system before becoming a trike.
"Guess what it is and I'll let you drive it", he said.
The valve covers told me nothin'...
"Well, it's either a Cadillac Eldorado or an Oldsmobile Toronado engine, but I can't tell which."
"Close enough" he says. "It's a 455 Olds."
Four-Hundred Fifty-Five cubic inches powering a machine that probably weighed less than 1500 pounds! He gave me the keys, then jumped on my Yamaha XS1100 to give chase. That trike was so powerful, to change lanes on the Interstate all you had to do was twist the throttle hard...
The front tire would leave the pavement and torque would move the bike one lane to the right, (controllably!)
It was a neat thing... everyone on the road pointed and waved.
It got 15 m.p.g., and since the seat back was attached to the radiator it wasn't comfortable to ride it long distances, even if you COULD afford the gas bill.
The trike in the photo above is a "Can-Am Spyder".
It's a neat concept. There's a dealer about 30 minutes away from us doing a pretty decent job of sellin' 'em.
It's obviously NOT a motorcycle.
I have a question I'd really like answered-
They get about 23 miles per gallon of fuel and take up almost as much room as a car...
Other than the fact that it's different, or unless you have some disability preventing you from riding two-wheels, why would anyone buy one?
Why not just buy a motorcycle with a sidecar rig?
On the other hand, if someone comes out with something like this I'll REALLY be interested!